12cR2 new features for Developers and DBAs - Here is my pick (Part 2)

In Part 1, I have outlined a few (my pick) 12cR2 new features useful for Developers and DBAs. In the part 2, I am going to discuss a few more new features.

Read/Write and Read-Only Instances

Read-write and read-only database instances of the same primary database can coexist in an Oracle Flex Cluster.

Advanced Index Compression

Prior to this release, the only form of advanced index compression was low compression. Now you can also specify high compression. High compression provides even more space savings than low compression.

PDBs Enhancements

• I/O Rate Limits for PDBs
• Different character sets of PDBs in a CDB
• PDB refresh to periodically propagate changes from a source PDB to its cloned copy
• CONTAINERS hint : When a CONTAINERS ()query is submitted, recursive SQL statements are generated and executed in each PDB. Hints can be passed to these recursive SQL statements by using the CONTAINERS statement-level hint. 
• Cloning PDB no longer to be in R/W mode : Cloning of a pluggable database (PDB) resolves the issue of setting the source system to read-only mode before creating a full or snapshot clone of a PDB.
• Near Zero Downtime PDB Relocation:This new feature significantly reduces downtime by leveraging the clone functionality to relocate a pluggable database (PDB) from one multitenant container database (CDB) to another CDB. The source PDB is still open and fully functional while the actual cloning operation is taking place.
• Proxy PDB: A proxy pluggable database (PDB) provides fully functional access to another PDB in a remote multitenant container database (CDB). This feature enables you to build location-transparent applications that can aggregate data from multiple sources that are in the same data center or distributed across data centers.

Oracle Data Pump Parallel Export of Metadata: The PARALLEL parameter for Oracle Data Pump, which previously applied only to data, is extended to include metadata export operations. The performance of Oracle Data Pump export jobs is improved by enabling the use of multiple processes working in parallel to export metadata.

Renaming Data Files During Import

Oracle RAC :

• Server Weight-Based Node Eviction :Server weight-based node eviction acts as a tie-breaker mechanism in situations where Oracle Clusterware needs to evict a particular node or a group of nodes from a cluster, in which all nodes represent an equal choice for eviction. In such cases, the server weight-based node eviction mechanism helps to identify the node or the group of nodes to be evicted based on additional information about the load on those servers. Two principle mechanisms, a system inherent automatic mechanism and a user input-based mechanism exist to provide respective guidance.
• Load-Aware Resource Placement : Load-aware resource placement prevents overloading a server with more applications than the server is capable of running. The metrics used to determine whether an application can be started on a given server, either as part of the startup or as a result of a failover, are based on the anticipated resource consumption of the application as well as the capacity of the server in terms of CPU and memory.

Enhanced Rapid Home Provisioning and Patch Management

TDE Tablespace Live Conversion: You can now encrypt, decrypt, and rekey existing tablespaces with Transparent Data Encryption (TDE) tablespace live conversion. A TDE tablespace can be easily deployed, performing the initial encryption that migrates to an encrypted tablespace with zero downtime. This feature also enables automated deep rotation of data encryption keys used by TDE tablespace encryption in the background with zero downtime.

Fully Encrypted Database: Transparent Data Encryption (TDE) tablespace encryption is applied to database internals including SYSTEM, SYSAUX, and UNDO.

TDE Tablespace Offline Conversion: This release introduces new SQL commands to encrypt tablespace files in place with no storage overhead. You can do this on multiple instances across multiple cores. Using this feature requires downtime, because you must take the tablespace temporarily offline. With Data Guard configurations, you can either encrypt the physical standby first and switchover, or encrypt the primary database, one tablespace at a time.